Butyl methoxydibenzoylmethanes

Butyl methoxydibenzoylmethane, or BMDBM and avobenzone for short, is a substituted 1,3-diketone. Butyl methoxydibenzoylmethane is a soluble organic UV filter which absorbs UV-A rays of about 320 to 400 nm with an absorption maximum at 357 nm (UVA range). The maximum concentration of butyl methoxydibenzoylmethane in cosmetic applications is 5%.

Due to the photoreactivity the light protection effect of butyl methoxydibenzoylmethane decreases. This reduction in function can be reduced by adding photostable organic UV filters as e.g. bis-ethylhexyloxyphenol methoxyphenyl triazine (Tinosorb S) (Chatelain E et al. 2001). Contact sensitizations by butyl methoxydibenzoylmethanes have been described (de Groot AC et al. 1987).

Butyl methoxydibenzoylmethane, under the name "avobenzone", is the most important UV-A filter in sunscreens on the American market.

1. Chatelain E et al (2001) Photostabilization of butyl methoxydibenzoylmethane (Avobenzone) and ethylhexyl methoxycinnamate by bis-ethylhexyloxyphenol methoxyphenyl triazine (Tinosorb S), a new UV broadband filter. Photochemical photobiol 74:401-406.
2. Gange RW et al (1986) Efficacy of a sunscreen containing butyl methoxydibenzoylmethane against ultraviolet A radiation in photosensitized subjects. J Am Acad Dermatol15:494-499.
3. de Groot AC et al (1987) Contact allergy to butyl methoxydibenzoylmethanes. Contact dermatitis 16:278.